Tissue engineering of blood vessels

Abstract

Method and apparatus for mapping the shape and dimensions of a 3-dimensional body, by applying to the 3-dimensional body a stretchable covering configured and dimensioned such that in its stretched condition it tightly engages and conforms to the shape and dimensions of the 3-dimensional body to be mapped. The stretchable covering carries a plurality of reference devices, such as bands and/or markers which are at know or determinable reference locations in an initial condition of the covering, and which change their locations in the stretched condition of the stretchable covering according to the shape and dimensions of the 3-dimensional body covered thereby. The locations of the markers on the stretchable covering are determined after the stretchable covering has been applied to the 3-dimensional body, and are utilized to produce a map of the shape and dimensions of the 3-dimensional body.

The invention claimed is: 
     
       1. A vessel sheath, comprising:
 a first network comprising first fibers having a first resorption rate; 
 a second network comprising second fibers having a second resorption rate; and 
 a third network comprising third fibers having a third resorption rate, wherein the third resorption rate is slower than the second resorption rate; 
 wherein said networks are positioned adjacent to one another and interwoven together to form a single sheath layer; and 
 wherein said single sheath layer is configured so to form a tubular shape around a single axis; 
 wherein all three networks of the single sheath layer are porous and are exposed to the same internal environment; and 
 wherein when the sheath is externally wrapped around the vessel, the vessel is allowed to expand to the limits allowed by said networks of fibers and re-engineer itself according to a pressure within the vessel. 
 
     
     
       2. The vessel sheath of  claim 1 , wherein the second fibers and the third fibers comprise at least one waveform. 
     
     
       3. The vessel sheath of  claim 1 , wherein the second resorption rate is slower than the first resorption rate. 
     
     
       4. The vessel sheath of  claim 3 , wherein the first fibers comprise a straight configuration. 
     
     
       5. The vessel sheath of  claim 1 , wherein the first fibers are less distensible than the second fibers and the third fibers. 
     
     
       6. The vessel sheath of  claim 1 , wherein the first fibers are in a first sheath layer, wherein the second fibers are in a second sheath layer, and the third fibers are in a third sheath layer. 
     
     
       7. The vessel sheath of  claim 6 , wherein the first sheath layer is positioned between the vessel and the second sheath layer when the sheath is wrapped around the vessel. 
     
     
       8. The vessel sheath of  claim 1 , wherein the second fibers are thicker than the first fibers. 
     
     
       9. The vessel sheath of  claim 8 , wherein the third fibers are thicker than the second fibers. 
     
     
       10. A vessel sheath, comprising:
 a first network comprising first fibers having a first resorption rate; 
 a second network comprising second fibers having a second resorption rate; and 
 a third network comprising third fibers having a third resorption rate; 
 wherein said networks are interwoven together to form a single sheath layer; 
 wherein the sheath is externally wrapped around the vessel in a tubular structure; 
 the tubular structure having a first diameter limit, a second diameter limit and a third diameter limit; 
 the first diameter limit being smaller than the second diameter limit and the second diameter limit being smaller than the third diameter limit; 
 wherein the tubular structure is at the first diameter limit when initially wrapped around the vessel; 
 wherein the tubular structure is expandable to the second diameter limit when the first network is resorbed; and 
 wherein the tubular structure is expandable to the third diameter limit when the second network is resorbed; and 
 wherein the fibers of the three networks are cross-connected so as to limit the expansion of the fibers of the third network of the tubular structure to the first diameter limit and the second diameter limit; 
 wherein the vessel is allowed to expand to the diameter limits allowed by said networks of fibers and re-engineer itself according to a pressure within the vessel. 
 
     
     
       11. The vessel sheath of  claim 10 , wherein the second resorption rate is slower than the first resorption rate. 
     
     
       12. The vessel sheath of  claim 11 , wherein the third resorption rate is slower than the second resorption rate. 
     
     
       13. The vessel sheath of  claim 10 , wherein the first fibers are in a first sheath layer, wherein the second fibers are in a second sheath layer, and the third fibers are in a third sheath layer. 
     
     
       14. The vessel sheath of  claim 10 , wherein said networks are positioned adjacent to one another. 
     
     
       15. A vessel sheath, comprising:
 a first network comprising first fibers having a first resorption rate, a straight configuration, and a first thickness; 
 a second network comprising second fibers having a second resorption rate and a second thickness; and 
 a third network comprising third fibers having a third resorption rate and a third thickness and an initial wavy configuration; 
 wherein said networks are interwoven together to form a single sheath layer; 
 wherein the third resorption rate is slower than the second resorption rate, which is slower than the first resorption rate; 
 wherein the third thickness is thicker than the second thickness, which is thicker than the first thickness; and 
 wherein when the sheath is externally wrapped around the vessel in a tubular structure; 
 the tubular structure having a first diameter limit, a second diameter limit and a third diameter limit; 
 the first diameter limit being smaller than the second diameter limit and the second diameter limit being smaller than the third diameter limit; 
 wherein the tubular structure is at the first diameter limit when initially wrapped around the vessel; 
 wherein the tubular structure is expandable to the second diameter limit when the first network is resorbed; and 
 wherein the tubular structure is expandable to the third diameter limit when the second network is resorbed and due to the expansion of the third network due to the wavy configuration of the third fibers; and 
 the vessel is allowed to expand to the diameter limits allowed by said networks of fibers and re-engineer itself according to a pressure within the vessel. 
 
     
     
       16. The vessel sheath of  claim 15 , wherein said networks are positioned adjacent to one another.